1. Field of the Invention
The present invention relates to an insertion sleeve and stiffener to be utilized with a stab-type coupler designed to couple a pipe to a coupler fitting. In particular, the present invention is directed to an insertion sleeve for a pipe coupler which will eliminate the need to chamfer the end of the pipe and will lessen the requirement to cut the pipe perpendicular to the pipe axis.
2. Prior Art
The insertion sleeve of the present invention is designed to operate with a stab-type coupler which is inserted manually onto the end of a length of plastic pipe. The pipe may be engaged with the coupler by axial insertion but the extraction of the pipe from the coupler cannot be accomplished. To insert, the plastic pipe is pushed on and over a rigid stiffener. Additionally, the stab-type connector forms a sealed, leak-proof communication between the pipe and the coupler and in some embodiments with another object, such as another length of pipe. It is desirable to employ a minimum number of parts that might be dropped or lost so that the coupler is easy to use in field applications.
Thermoplastic piping is generally produced by extrusion of long lengths which are then cut, often times at the field installation location, to a desired length or lengths. The thermoplastic pipe may be composed of a variety of materials, such as polyvinyl chloride (PVC), polyethylene (PE), or acrylonitrile-butadiene styrene (ABS).
During field installation, when the thermoplastic pipe is cut to a desired length, the end is typically cut off perpendicular to the axis of the pipe. The face of the pipe end is ideally flat, although because of many conditions and situations encountered in the field, this may not always be the case.
Some stab-on couplings provide a seal between the coupling and the outside circumference of the plastic pipe. Others, such as Assignee's Patent (U.S. Pat. No. 5,692,785 for “Plastic Pipe Coupler With Internal Sealer” to Wartluft and Wood which is incorporated herein by reference) provide a seal between the coupling and the inside of the plastic pipe. Since the outside surface of the plastic pipe is easily scratched or damaged, this is an advantageous arrangement.
Moreover, before the pipe end is inserted into a fitting, it has been found to be desirable to provide a beveled edge to the pipe end.
In some applications, it is desirable to have the bevel on the outside edge (to the outside diameter of the pipe). In other applications, it is desirable to have a bevel on the inside edge (to the inside diameter of the pipe). In further applications, it is desirable to have a bevel on both the outside and on the inside edges. This allows for easier installation into the socket depths of the coupling and will also allow the leading front edge of the plastic pipe to pass over O-rings or other seals without unseating the seals or O-rings.
In the past, a number of measures have been taken to achieve this result. Chamfering or beveling of pipe ends has been performed by shaving with a blade.
One such tool similar to a pencil sharpener has an angled blade oriented in a holder. Examples are seen in Muse (U.S. Pat. No. 2,838,773) and Dackow (U.S. Pat. No. 3,595,107). While these tools adequately put a bevel on the edge or on the edges, they also leave shavings or chips in the process.
Another solution to placing a beveled edge on the pipe end is seen in Assignee's own U.S. Pat. No. 5,853,272 for a “Plastic Pipe End Forming Tool”. Inside, outside, or both inside and outside bevels are formed into the end of a plastic pipe.
Notwithstanding the foregoing, it would be desirable to eliminate the requirement of placing a beveled edge on a plastic pipe end prior to engaging a stab-on coupler.
It would additionally be desirable to provide a stab-on coupling which would accommodate a pipe end that is not exactly perpendicular to the axis of the pipe.
It would also be desirable to provide an insertion sleeve for a coupler to eliminate the need to chamfer the end of a pipe.
It would also be desirable to provide a coupler having a stiffener that would accommodate an insertion sleeve.